1. Field of Invention
The present invention relates to a backlight module. More particularly, the present invention relates to a hollow edge-type backlight module with a light-emitting array.
2. Description of Related Art
A backlight module is one of the key components for a liquid crystal display (LCD) panel. Since liquid crystals themselves do not emit light, the backlight module is required for providing a light source, whereby the LCD panel can show a normal image of uniform brightness. In general, a backlight module has two type designs: a direct-type design and an edge-type design and the backlight module always comprises a backlight source such as a Cold Cathode Fluorescent Lamp (CCFL) and a light emitting diode (LED), etc.
With the advent of liquid crystal display (LCD) technologies, a local dimming control technology has played an important part in the LCD market, which may greatly promote the additional value of a LCD, and has become an emphasized item for LCD manufacturers. The local dimming control technology is to divide the backlight source of the LCD into a plurality of blocks, and then to control the brightness of each block in accordance with a display image. Broadly speaking, the local dimming control technology can be classified into three categories: 0D dimming control, 1D dimming control and 2D dimming control, wherein the 2D dimming control has the best effect. A conventional skill uses a direct-type LED backlight module to implement the 2D dimming control technology, which has the advantages of high dynamic contrast and energy saving. However, the direct-type LED backlight module is too thick, and thus the requirement of thin products cannot be met.
Another conventional skill overlaps a plurality of wedge light guide plates to obtain a structure of edge-type backlight module. Although this structure of edge-type backlight module can be applied to the local dimming control and has a relatively small thickness, yet its assembling steps are too complicated. Furthermore, its assembly variances will cause differences among respective blocks of the backlight module, so that it is quite difficult to actually overlap several light guide plates to obtain a backlight module of large size or special size.